Plural coated sheet material

ABSTRACT

Improved adherence is obtained for sheet material having a hydrophobic film support or base, such as a hydrophobic cellulose ester or polyester, by the combination of a vinyl polymer subbing layer arranged directly on the hydrophobic support, the subbing layer being formed of a copolymer containing at least 45 percent by weight of vinylidene chloride and/or vinyl chloride monomer along with a minor amount of a hydrophilic vinyl monomer with the balance being constituted by any other vinyl monomer, and superimposed upon the vinyl subbing layer a layer containing a mixture of gelatin with a copolymer of butadiene and a vinyl monomer containing 30-70 percent by weight of butadiene, the ratio of the gelatin to the butadiene copolymer being in the range of 1:3 to 2:1 by weight. An additional layer can be applied over the gelatin/copolymer layer and constituted by such ingredients as are desirable for the particular utility of the resultant sheet material, such as light-sensitive silver halide emulsion photographic layers, electrophotographic layers containing finely divided photoconductive material such as zinc oxide or some other photosensitive semiconductive material, matte layers containing pigment, diffusion transfer layers containing development nuclei and so on. Alternatively, the ingredients appropriate to some particular ultimate utility can be incorporated into the gelatin/butadiene copolymer layer directly.

United States Patent Van Paesschen et al.

[4 Mar. 14, 1972 [54] PLURAL COATED SHEET MATERIAL [73] Assignee:Gevaert-Agfa N.V., Mortsel, Belgium [22] Filed: Sept. 27, 1968 [21]Appl. No.: 763,382

[30] Foreign Application Priority Data Sept. 28, 1967 Great Britain..44,l14/67 [52] US. Cl. ..ll7/83, 96/1 PC, 96/15,

96/1 .8, 96/67, 117/7, 117/68, 117/76 F, 117/1388 F, 117/1388 UA,117/145 [51 Int. Cl. ..B32b 23/08, B32b 27/08, G03c 1/80 [58] FieldofSearch v.l 17/83. 81, 76 F, 164,138.8 F; 260/8 [56] References CitedUNITED STATES PATENTS 2,491,023 12/1949 Alles et a1 ..117/76 F 2,779,684l/1957 Alles ..117/83 X 2,865,753 12/1958 Griffin et a1... ..260/8 X2,982,651 5/1961 Mackey ....117/81 X 3,052,543 9/1962 Bauer et al .1117/81 X 3,143,421 8/1964 Nadeau et al. ..117/81 X 3,370,951 2/1968Hasenauer et al. ..117/76 F X FOREIGN PATENTS OR APPLICATIONS 1,053,04312/1966 Great Britain ..260/8 Primary Examiner-William D. MartinAssistant Examiner-Ralph Husack Attorney-William J. Daniel [5 7]ABSTRACT Improved adherence is obtained for sheet material having ahydrophobic film support or base, such as a hydrophobic cellulose esteror polyester, by the combination of a vinyl polymer subbing layerarranged directly on the hydrophobic support, the subbing layer beingformed of a copolymer containing at least 45 percent by weight ofvinylidene chloride and/or vinyl chloride monomer along with a minoramount of a hydrophilic vinyl monomer with the balance being constitutedby any other vinyl monomer, and superimposed upon the vinyl subbinglayer a layer containing a mixture of gelatin with a copolymer ofbutadiene and a vinyl monomer containing 30-70 percent by weight ofbutadiene, the ratio of the gelatin to the butadiene copolymer being inthe range of 1:3 to 2:1 by weight. An additional layer can be appliedover the gelatin/copolymer layer and constituted by such ingredients asare desirable for the particular utility of the resultant sheetmaterial, such as light-sensitive silver halide emulsion photographiclayers, electrophotographic layers containing finely dividedphotoconductive material such as zinc oxide or some other photosensitivesemiconductive material, matte layers containing pigment, diffusiontransfer layers containing development nuclei and so on. Alternatively,the ingredients appropriate to some particular ultimate utility can beincorporated into the gelatin/butadiene copolymer layer directly.

18 Claims, No Drawings PLURAL COATED SHEET MATERIAL This inventionrelates to sheet material which comprises a hydrophobic support film anda layer system which is capable, if so desired, of providing a bondbetween a hydrophilic layer and the said hydrophobic support film,provide a vehicle for light-sensitive material as hereinafter described,and particularly relates to film recording materials, films and foilsconsisting of or comprising said sheet material.

In the following description and claims the terms photographic filmelements and film recording materials include elements and materials foruse in a variety of photoreproduction systems. Examples of such systemsinclude the wellknown use of light-sensitive silver halide emulsions,electrographic and electrophotographic systems, and a recently developedphotosensitive system wherein the recording is effected by means ofphotosensitive semiconductive substances.

In the said recently developed photosensitive systems, images areproduced by the action of electromagnetic radiation on photosensitivesemiconductor compounds, compositions or materials, which are reversiblyactivated by patterns of radiations to create a latent image ofcorresponding activated patterns. The latent image is capable ofproducing a chemical reaction with a dissolved reactant by anoxidationreduction chemical process to form a visible image (seeUnconventional Photographic Systems, Second Symposium, Oct. 26-28, 1967,Washington D.C., pages 116-117).

In electrographic systems, electrostatic charges are applied to aninsulating surface. In such process an electrostatic charge pattern isbuilt up on an insulating layer, e.g., by means of a modulated electronbeam, while a conductive element, e.g., a conductive support or layerstands in electrical contact with the backside of said insulating layer,to which a voltage is applied. After the patternwise charging of theinsulating layer, the electrostatic charge pattern is developed, forinstance by the application of a powder. Before powder development, theconductive backing element may be removed ifdesired. An alternativedevelopment technique is to bring about an imagewise deformation (rippleimage) of the insulating layer as hereinafter described.

In electrophotographic systems, the recording of images is based on adifferentiation in electrostatic charge condition, chargeability orelectrical conductivity, of a recording layer containing aphotoconductive substance, the said layer initially being electricallyinsulating in the absence of light, but becoming electrically conductiveon exposure to light, and being in electrical contact with anelectroconductive support or layer. By imagewise exposing the recordinglayer to imagewise modulated activating electromagnetic radiation, apattern of the said differential charge condition is obtained. Theelectrostatic charge images may be developed by an electrostaticallyattractable marking material, or the conductivity images byelectrolysis.

A particular technique of developing the latent image on a recordinglayer from either an electrographic or an electrophotographic processinvolves the deformation of the exposed areas to produce a so-calledripple image, by imagewise distortion of the surface under the influenceof a differential electrical potential between the recording element andthe backing element, and reference may be made to United Kingdom Patentspecification No. 964,881; to Photographic Science and Engineering",Vol. 7, No. l (1963) pages 12-13; to RCA Review, Dec. 1964, pages692-709, and to United Kingdom Patent application No. 5307/66.

In the manufacture of photographic film elements for use in silverhalide emulsion layer systems, it is common practice to apply to thefilm support before the light-sensitive silver halide emulsion layer orother colloid layers are applied, a thin subbing layer consisting mainlyof gelatin. If such a subbing layer is omitted, the photographicemulsion layer or the other colloid layers will not adhere sufficientlyto the base.

The invention consists of a hydrophobic support film carrying superposedthereon in succession, a layer (A) which is directly adherent to thesaid hydrophobic support film and comprises a copolymer formed from 45to 99.5 percent by or which may itself weight of at least one of thechlorine-containing monomers vinylidene chloride and vinyl chloride,from 0.5 to 10 percent by weight of an ethylenically unsaturatedhydrophilic monomer, and from 0 to 54.5 percent by weight of at leastone other copolymerizable ethylenically unsaturated monomer; and a layer(B) comprising in a ratio of 1:3 to 1:05 by weight of a mixture ofgelatin and a copolymer of 30 70 percent by weight of butadiene with atleast one copolymerizable ethylenically unsaturated monomer.

Hydrophobic support films suitable for use in the sheet materialaccording to the invention, include, e.g., a hydrophobic celluloseester, e.g., cellulose acetate, cellulose aceto-butyrate and cellulosenitrate; or a highly polymeric linear polyester such as for examplepolyethylene terephthalate, polystyrene or polymethacrylic acid esters.Such hydrophobic support films are coated with successive layers (A) and(B) according to the invention to provide a layer system which may beused for a variety of purposes. Thus the sheet material may be used forthe transference thereto of a hydrophilic layer. Thus in recording orreproduction systems such a hydrophilic layer may be a stripped-offhydrophilic layer carrying a relief pattern. The sheet materialaccording to the invention may be wetted with a liquid system capable ofproviding a hydrophilic film thereon. Thus the sheet material accordingto the invention may contain in the said layer (B) photosensitivesemiconductor compounds, compositions or materials which are reversiblyactivated by patterns of radiations to create a latent image, and thesaid liquid system may then be an aqueous developing solution for thedevelopment of such a latent image.

As described a hydrophilic layer may be applied to layer (B) of thesheet material according to the invention which hydrophilic layer maybe, e.g., either transferred from another material or produced thereonfrom a liquid system. Both layer (B) and the hydrophilic layer whenpresent, may contain one or more other substances, e. g., as follows;

a. semiconductive substance(s) in a suitable binding agent b.electroconductive agent(s) in a suitable binding agent c. pigment(s) ina photohardenable or photosolubilizable binder d. matting agent(s) oropaque white pigment(s) in a suitable binder e. light-sensitivesubstance(s) including light-sensitive silver halide, photoconductivesubstances, and other light-sensitive compounds, e.g., diazonium saltsand diazo-sulphonates f. dissolved dye(s), e.g., a dye that isbleachable g. color coupler(s) e.g., a color coupler that is used insilver halide color photography h. developing nuclei suited in theproduction of silver images according to the silver halide complexdiffusion transfer process.

The sheet material according to the invention may be used as a wrappingmaterial, particularly when having layers thereon particularly adaptedto accept printing thereon, or the sheet material may be used as tracingfilm.

Particularly useful recording materials are provided by sheet materialaccording to the invention, having hydrophilic pigment coatings thereon,e.g., pigmented gelatin coatings suited for the production of reliefimages, which are produced by means of a photohardening orphoto-solubilizing reaction. Such pigment coatings are of practicalinterest in the graphic art more particularly in the field known ascolor proofing. Color proofing materials serve to form a showing prooffor submission for approval, whereby an idea may be obtained of themulticolor halftone reproduction which will finally be produced by thesuccessive printing in register with separate standard inks yellow,magenta, cyan and black.

For ease of reference, the layer formed from the copolymer of vinylidenechloride and/or vinyl chloride is hereinafter referred to as thevinylidene chloride copolymer layer, and the layer formed with themixture of gelatin and butadiene copolymer is hereinafter referred to asthe copolymer layer.

butadiene The vinylidene chloride copolymer comprises from 0.5 topercent by weight of ethylenically unsaturated hydrophilic monomericunits. These units may be derived from ethylenically unsaturated monoordicarboxylic acids such as acrylic acid, methacrylic acid, and itaconicacid. Other hydrophilic units, e.g., those derived from N vinylpyrrolidone, may be present.

The vinylidene chloride copolymer may be formed from vinylidene chlorideand/or vinyl chloride and hydrophilic monomeric units alone in the ratioindicated above. Preferably up to 54.5 percent by weight of otherrecurring units, for instance acrylamides, methacrylamides, acrylic acidesters, methacrylic acid esters, maleic esters and/or N-alkylmaleimides,may also be present.

Suitable vinylidene chloride copolymers are, e.g.,:

the copolymer of vinylidene chloride, N-tert.-butylacrylamide, n-butylacrylate, and N-vinyl pyrrolidone (70:23:3z4),

the copolymer of vinylidene chloride, N-tert.-butylacrylamide, n-butylacrylate, and itaconic acid (70:21:52),

the copolymer of vinylidene chloride, N-tert-butylacrylamide, anditaconic acid (88zl0z2),

the copolymer of vinylidene chloride, n-butylmaleimide, and itaconicacid (901822),

the copolymer of vinyl chloride, vinylidene chloride, and methacrylicacid (657305 the copolymer of vinylidene chloride, vinyl chloride, anditaconic acid (70:26: 1),

the copolymer of vinyl chloride, n-butyl acrylate, and itaconic acid(66:30:4),

the copolymer of vinylidene chloride, n-butyl acrylate, and itaconicacid (80:1 8:2),

the copolymer of vinylidene chloride, methyl acrylate, and itaconic acid(902822),

the copolymer of vinyl chloride, vinylidene chloride, N-tert.-butylacrylamide, and itaconic acid (50:30: 1 8:2).

All the ratios given between brackets in the above-mentioned copolymersare ratios by weight.

The above copolymers are only examples of the combinations, which can bemade with the different monomers, and the invention is not limited atall to the copolymers enumerated.

The different monomers indicated above may be copolymerized according tovarious methods. For example, the copolymerization may be conducted inaqueous dispersion containing a catalyst and an activator.Alternatively, polymerization of the monomeric components may occur inbulk without added diluent, or the monomers are allowed to react inappropriate organic solvent reaction media.

The vinylidene chloride copolymers may be coated on the hydrophobic filmbase according to any suitable technique, e.g., by immersion of thesurfaces of the film into a solution of the coating material. They mayalso be applied by spray, brush, roller, doctor blade, air brush, orwiping techniques. The thickness of the dried layer may vary between 0.3and 3 1. preferably.

Various wetting or dispersing agents may be used when the vinylidenechloride copolymer layer is applied from an aqueous dispersion. Thesedispersions are obtained directly when the copolymer has been made by anemulsion polymerization process. When coating aqueous dispersions ofvinylidene chloride copolymer on a polyethylene terephthalate filmsupport a very strong adherence to the support is obtained when saiddispersions are applied before or during stretching of the polyethyleneterephthalate film. The aqueous dispersion may be applied to at leastone side of the nonstretched film, but may also be applied topolyethylene terephthalate film which has been oriented biaxially. Thevinylidene chloride copolymer layer may also be coated on at least oneside of a polyester film, which has been stretched in only onedirection, e.g., longitudinally, whereafter the subbed polyester film isstretched in a direction perpendicular thereto, in this casetransversally.

Finally, the biaxially oriented coated polyester film is provided withthe second subbing layer of the mixture of gelatin and butadienecopolymer latex.

The butadiene copolymer comprises 30 to percent by weight of monomericbutadiene units. The balance is formed by units deriving from otherethylenically unsaturated hydrophobic monomers, such as acrylonitrile,styrene, acrylic acid esters, methacrylic acid esters, and acrolein.

The butadiene copolymer is formed by emulsion polymerization and theprimary latex obtained is directly mixed with the aqueous gelatinsolutions in such a way that the ratio of gelatin to butadiene copolymerin the dried layer varies between 1:3 parts and 1:05, all parts being byweight. To the mixture known plasticizers for gelatin such aspolyethylene oxides and glycerol may also be added.

The mixture of aqueous gelatin solution and of butadiene copolymer latexis coated onto the vinylidene chloride copolymer layer by known means.The thickness of the dried layer generally varies between 0. l 0 and 20,u..

The addition of a latex of a copolymer of butadiene and a lower alkylester of acrylic or methacrylic acid to a gelatincontaining layer of aphotographic material has been described already in the United KingdomPatent specification No. 1,053,043. According to this Patentspecification the butadiene copolymer latex is added to reduce thebrittleness of the gelatin layer, to procure a higher dimensionalstability to the photographic material, wherein it is used, and todecrease its curling tendency. However, it cannot be deduced from thisPatent Specification that the layer of gelatin and butadiene copolymerlatex combined with a vinylidene chloride copolymer layer would procurean adequate subbing combination for any hydrophobic film support, andespecially for polyester film supports.

The subbed film support consists of a hydrophobic film support and thecombination of the two anchoring subbing layers used according to theinvention. As mentioned before the hydrophobic film support may be afilm of cellulose triacetate, of polyethylene terephthalate, ofpolycarbonate, of polystyrene, of polymethacrylic acid ester, etc. Thesubbed hydrophobic film support may be provided on only one side or onboth sides with the combination of subbing layers.

A colloid layer may be deposited on the subbed film support thusobtained. This colloid layer may be a simple gelatin layer, a gelatinsilver halide emulsion layer, a gelatin filter layer, a gelatin mattinglayer containing, e.g., finely divided silica, an antistatic layer or anantihalation layer containing a hydrophilic colloid binding agent. if anantistatic layer is deposited on the subbed film support, knownantistatic agents, e.g., salts, are dispersed in the colloid bindingagent, e.g., gelatin. in the latter case too, these salts may be addedalready to the aqueous gelatin solution, which is to be mixed with thebutadiene copolymer for the formation of the second layer of the subbinglayer combination.

In the manufacture of electrophotographic recording materials containinga hydrophobic electrically insulating film support and a photoconductivelayer containing a photoconductive substance applied in a binder,normally an electrically insulating binder, it is necessary to applybetween the photoconductive recording layer and the said support anelectrically conductive interlayer having a coiiductivity substantiallyhigher than the conductivity in the dark of the photoconductiverecording layer. Such an interlayer preferably contains a hydrophiliccolloid in combination with antistatic or hygroscopic agents, e.g.,those described in the U.S. Pat. No. 3,148,982, conductive pigments,e.g., carbon black and/or polyionic polymers, e.g., those containingquaternized nitrogen atoms as described in the United Kingdom Patentspecification No. 950,960. Good results are obtained with CALGONCONDUCTIVE POLYMER 261 manufactured by Calgon Corporation, Calgon CenterBox 1346, Pittsburgh, U.S.A. (Calgon is a registered Trademark). Suchantistatic or electroconductive hydrophilic colloid layers perfectlyadhere to hydrophobic film supports subbed according to the presentinvention.

In the manufacture of interesting photochemically recording materials,e.g., as described in the Belgian Patent specification No. 655,384 andthe published Dutch Patent application No. 641301 I, semiconductivelight-sensitive pigments are dispersed in a binder containing ahydrophilic colloid.

In the manufacture of interesting electrostatic recording materials,e.g., as described in the United Kingdom Patent application No.16,459/66, now British Pat. No. 1,156,822, and the published DutchPatent application No. 6608816 a n-type photoconductor pigment isdispersed in a binder having a hydrophilic character.

A hydrophobic film support is firmly bonded to such pigment coatings bymeans of the composite subbing layer according to the present invention.

In all the above-described applications of the combination of subbinglayers according to the invention, at least one layer is deposited ontop of the butadiene copolymer layer. The layer deposited thereon may bea simple hydrophilic colloid layer, e.g., a gelatin layer, a hydrophiliccolloid layer containing light-sensitive silver halide salts, ahydrophilic polymer or colloid layer containing all kinds of specialadditives such as antihalation dyestuffs, antistatic agents,electroconductive pigments, photoconductive insulating pigments,photosensitive semiconductive pigments and matting agents. All theseadditives may also be added already to the coating composition of thebutadiene copolymer layer. Thus, there can be incorporated into thebutadiene copolymer layer finely divided silicium dioxide,photosensitive titanium dioxide, photoconductive zinc oxide and carbonblack. According to a preferred embodiment these additives are dissolvedwhen they are soluble in the coating composition or homogeneouslydispersed in the mixture of aqueous gelatin solution and butadienecopolymer latex before casting of the second subbing layer on top of thevinylidene chloride copolymer layer. When the subbed hydrophobic filmsupport is to be used as a tracing film support, there may be added tothe butadiene copolymer layer, which already contains a white pigment,e.g., titanium dioxide and/or silicium dioxide, also urea-formaldehydeor melamine-formaldehyde resins to render the surface of the layer moreresistant to writing and tracing operations.

In a particular embodiment of the invention a n-type photoconductivesubstance, e.g., photoconductive zinc oxide is dispersed in thebutadiene copolymer layer and no further radiation sensitive layers aredeposited on top of the said layer. In this way a photographic materialis produced, which is suited for use according to the process describedin the United Kingdom Patent application No. 16,459/66, now British Pat.No. 1,l56,822.

According to a special and very interesting embodiment of the inventiona photosensitive semiconductor material is dispersed in the butadienecopolymer layer and no further radiation-sensitive layers are depositedon top of the said layer. In this way a photographic recording materialis obtained by which visible or latent images can be formed in theabsence of an externally applied electric field by means of theimagewise modulated action of electromagnetic radiation reversiblyactivating the photosensitive semiconductor material in such a way thatby means of a dissolved reactant, a portion of which may be present inthe recording material before the exposure, images corresponding to thelight-activated pattern are produced by an oxidation-reduction reaction,the said photosensitive semiconductor itself being substantiallychemically unchanged at the end of the process, So, the recordingmaterial according to the present invention is composed of a hydrophobicfilm support coated with the vinylidene chloride copolymer layer andhaving thereon the butadiene copolymer layer, in which thephotosensitive semiconductor material is dispersed. Photosensitivesemiconductor compounds suited for use in a process for producingvisible or latent images by an oxidation-reduction reaction as indicatedabove are described, e.g., in the United Kingdom Patent specificationNo. 1,043,250, which pertains to a related process. Titanium dioxide isof special interest as semiconductor material, but other knownsemiconductors, which become conductive on irradiation, can also beused, e.g., zinc oxide, zinc sulphide, lead monoxide, red lead oxide,silicium dioxide, aluminum dioxide, chromium oxide, osmium oxide, andcadmium sulphide.

In the said process the average particle size of the finely dividedsemiconductors is important. Particle sizes not larger than 250millimicrons and preferably comprised between 5 and millimicrons arevery advantageous.

The finely divided semiconductor is dispersed in the abovedescribedbinder material consisting of gelatin and butadiene copolymer in such aproportion that in the dried layer the ratio of binding agent tosemiconductor varies between 3:] and 1:10 by weight. The thickness ofthe radiation-sensitive coating applied on the vinylidene chloridecopolymer layer by known means should be generally situated between 0.10and 20 p. after drying.

Activation of the semiconductor surfaces is effected by exposure toradiation of sufficient energy. Ultraviolet radiation having awavelength of less than approximately 4,000 A. is very appropriate.However sensitization of the semiconductors, e.g., by doping withforeign ions or dye sensitization techniques can be employed to make thesemiconductor sensitive to radiation in the visible spectrum.

Exposure to a suitable source of radiation modified by an image patternestablishes gradients of differential chemical reactivity between theexposed and nonexposed portions and establishes an image pattern in theexposed portions of the semiconductor material. Said image pattern isreversible and can be erased therefrom, e.g., by heating. It can also bemade permanent by bringing the activated portions in contact withsuitable oxidizing or reducing agents according to known techniques.This reaction forms a visible image pattern.

The reversible image, which was obtained upon exposure to a source ofradiation need not be treated with the oxidizing or reducing agentsdirectly after exposure. It can be stored for a certain time and at alater stage it can be erased or developed to produce either positive ornegative images corresponding with the image stored in the exposedsemiconductor. After development, the semiconductor surface isthoroughly washed to remove any remaining developer, whereupon thesemiconductor surface can be reused if new information should be addedto the already developed image. For development, numerous developersincluding silver ions, can be employed.

If the degree of semiconductor activation is high, the quantity of,e.g., metallic silver formed by reduction of silver ions by thelight-activated photoconductor will be sufficient to form a visibleimage directly. If not so, a latent developed image is produced in thesemiconductor. Such an image is irreversible and can be stored for longperiods. It can also be intensified by an image intensificationdevelopment according to which, e.g., solutions containing substancessuch as univalent silver ions, mercurous ions, and mercuric ions, whichare reducible by the light-activated semiconductor to finely dividedblack-appearing metallic silver or mercury, are used in combination withchemical redox systems, preferably organic redox systems such as thosecontaining hydroquinone or p-monomethylamino-phenol sulphate.

After development the semiconductor surfaces are rendered incapable offurther development by thoroughly washing, e.g., in water containing asolubilizing or complexing agent to aid removal of residual developer.In an analogous manner as in the fixing solutions employed in silverhalide photography, such solutions solubilize the remaining developer,e.g., silver ion, and they facilitate the removal thereof by washing.

In contradistinction with the above-described process for forming anirreversible image in a semiconductive layer, it is also possible tosoak the semiconductive layer before the exposure with a solution of thedeveloper. In this way there is immediately obtained an irreversibleimage upon exposure.

When hydrophobic film, e.g., polyester film was used as the support forthe radiation-sensitive semiconductor coating, at least two subbinglayers were needed hitherto, to obtain a sufficient adhesion between thesemiconductor coating and the support. The possibility of incorporatingthe photosensitive semiconductive substances in one of the subbinglayers ofiers the considerable advantage, that but two subbing layersmust be applied. With these two subbing layers the adhesion as well asthe photographic properties are excellent.

The following examples illustrate the present invention.

EXAMPLE 1 In a reaction flask equipped with a stirrer, a nitrogen inlet,a dropping funnel, and a condenser were placed l liters of water and2.88 liters of a 10 percent aqueous solution of the sodium saltsulphonated dodecyl benzene. Then the reaction flask was rinsed withnitrogen and the liquid was heated to 60 C. In another flask were placedsuccessively 800 cc. of isopropanol, 144 g. of N-vinyl-pyrrolidone, 108g. of n-butyl acrylate, 830 g. of N-tert.-butylacrylamide and 2,520 g.of vinylidene chloride. The mixture was stirred and brought todissolution by gentle heating.

Through the dropping funnel a solution was added of 21 .6 g. of ammoniumpersulphate in 400 cc. of water. Immediately pumping of the monomersolution into the reaction flask was started. The rate ofpumping wassuch that after 75 min. all the monomer solution was pumped over.Together with the monomer solution a further amount of ammoniumpersulphate solution was added dropwise (64.8 g. in 1,200 cc. of water).During the whole reaction period the temperature of the mixture wasmaintained at 60 C. while refluxing. After all the monomer had beenadded, again an amount of 21.6 g. of ammonium persulphate dissolved in400 cc. of water was added at once. After refluxing, stirring wascontinued for another 30 min. at 60 C., whereupon the reaction mixturewas cooled to room temperature.

in order to precipitate the copolymer of vinylidene chloride,N-tert.-butylacrylamide, n-butyl acrylate, and N-vinyl-pyrrolidone(70:23:314), the latex formed was poured into a mixture of 40 liters of10 percent aqueous sodium chloride solution and 40 liters of methanolwhile stirring. The fine grainy precipitate which was obtained wasrepeatedly washed with water and finally dried.

An amount of 2.5 g. of the vinylidene chloride copolymer formed abovewere dissolved in a mixture of 90 cc. of hutanone and 10 cc. ofnitroethane. The solution obtained was warmed to 25 C. and coated on aplate of polymethyl methacrylate in such a way that 0.75 to 1.0 g. ofcopolymer was present per sq.m. This layer was dried at roomtemperature.

To the subbing layer obtained a second layer was applied at to 50 C. ina ratio of 0.4 to 0.6 g./sq.m from the following composition:

20 7: latex of copolymer of butadiene and methyl methacrylate preparedas described hereinafter l0 g. gelatin 1 g. water 55 cos.

acetone ccs. methyl glycol 5 cos.

After drying, a light-sensitive gelatin silver halide emulsion layer ascommonly used in the graphic art was applied to this layer. The layersof the photographic material manufactured in this way showed a goodadherence before, during as well as after processing in the photographicbaths.

The copolymer latex was prepared as follows:

In a 20 liters autoclave were placed successively:

water boiled under nitrogen 10.2 l. 10 7: aqueous solution ofoleylmethyl tauride 0.6 l. l0 7: aqueous solution of the sodium salt ofheptadecyl-disulphobenzimi dazole 0.6 l. azodiisobutyronitrile 6 g.methyl methacrylate 1500 g. butadiene 1500 g.

EXAMPLE 2 To a cellulose triacetate film a layer was applied at a ratioof 0.75 to l g./sq.m from the following composition at 25 C:

copolymer of vinylidene chloride, N-tert.-butyl-acrylamide, n-butylacrylatc, and N-vinyl pyrrolidone of example I 2 g.

acetone 50 cos. ethyl acetate 10 ccs. methanol l0 ccs. ethanol 10 cos.butanone 10 cos.

A second layer was applied to the resulting dried layer in a ratio of0.4 to 0.6 g./sq.m at 35-50 C. from the following composition:

20 7: latex of copolymer of butadiene and methyl methacrylate of exampleI 5 g. gelatin l g. water 60 ccs. methanol 40 ccs.

A light-sensitive gelatin silver halide emulsion layer was coatedthereon.

The layers of the photographic material thus obtained possessed anexcellent adherence in wet as well as in dry state.

EXAMPLE 3 In an autoclave were placed 1,650 cc. of water and 9.6 g. ofitaconic acid. After dissolution a solution of 6 g. of sodium hydrogencarbonate in 120 cc. of water was added. Subsequently 98 cc. of a 10percent aqueous solution of the disodium salt of disulphonated dodecyldiphenyl ether and 49 cc. of a 10 percent aqueous solution of the sodiumsalt of sulphonated dodecyl benzene were added as emulsifying agents.Then 96 g. of n butyl acrylate, 144 g. of vinylidene chloride, 9.8 g. ofammonium persulphate, and 4.9 g. of potassium metabisulphite were added.The autoclave was sealed and stirring started. Under nitrogen pressure240 g. of vinyl chloride were pressed into the autoclave, which was thenheated to 50 C., while stirring. When this temperature had been reached,stirring was continued for 15 to 30 min. The temperature of the latexrose to about 65 C. The reaction was continued for about 3 h. whereuponthe latex was cooled to room temperature. The pH thereof amounted to 2.6and was brought to 6 by means of 100 cc. of 1N aqueous sodium hydroxide.It was very well filterable and consisted of the copolymer of vinylidenechloride, vinyl chloride, n-butyl acrylate, and itaconic acid(30:50:1812) in a concentration of 20 percent.

To an extruded polyethylene terephthalate film, which had been stretchedlongitudinally up to three times its original length, a subbing layerwas applied in a ratio of about 2 g./sq.m from an aqueous suspensioncontaining:

20 latex of copolymer of vinylidene chloride, vinyl chloride, n-hutylacrylate and itaconic acid (30:50:18.2) (manufactured as above) finelydivided silica 500 g. S g.

latex of copolymer of butadiene and methyl methacrylate of example 1 7.5g. gelatin 1 g.

water 60 ccs. methanol 40 ccs.

This subbed film was provided with a light-sensitive gelatin silverhalide emulsion layer as commonly used for graphic purposes. The layersof photographic material thus obtained possessed a good adherence beforeas well as after processing.

EXAMPLE 4 To one side of a biaxially oriented polyethylene terephthalatefilm of 180 p. thickness a layer was applied at -30 C. in a ratio of 1.5to 1.75 g./sq.m from the following composition:

copolymer of vinylidene chloride, N-tert.-butyl-acrylamide, n-butylacrylate, and N-vinyl pyrrolidone ol'example l 5.5 g. methylene chloride65 cos. diehloroethane ccs.

After drying of the first layer, a second layer was applied thereto in aproportion of 0.4 g./sq.m from the following composition:

20 1? latex of copolymer of butadiene and methyl methacrylate of example1 6.25 g. gelatin 1 g. water 43 ccs. silica 0.5 g. polystyrene sulphonicacid 1.8 g. methanol ccs.

A gelatin silver halide emulsion layer as used in photographic X-raymaterial was then coated on this antistatic layer. The layers of thephotographic material thus obtained possessed a good adherence in allcircumstances.

EXAMPLE 5 To both sides of a biaxially oriented polyethyleneterephthalate film of 100 ,u. thickness a layer was applied from thefollowing composition at 25-30 C.:

copolymer of vinylidene chloride. N-terL-hutylacrylamide, n-bulylacrylate, and itaconic acid (70:2 l :5z4) prepared analogously to thevinylidene chloride copolymer of example l 7 g. methylene chloride 65ccs. dichloroethane 35 ccs.

This coating composition was applied in such a way that the dried layerhad a thickness of 1.5 to 1.75 To both subbing layers a layer wasapplied in a proportion of 0.4 to 0.6 g./sq.m from the followingcomposition at 35-50 C.:

20 Q latex of copolymer of butadiene and styrene (60:40) preparedanalogously to the latex of the copoly mer of butadiene of example I 5g:

gelatin M lg. 77* water 60 ccs. methanol 40 ccs.

EXAMPLE 6 Example 5 was repeated, with the difference, however, that thecoating composition for the second subbing layer was replaced by thefollowing one:

20 5% latex of copolymer of butadiene and ethyl acrylate (50/50) 6.25 g.gelatin l 5. water 60 ccs. ethanol 40 ccs.

The adherence of the layers of the material obtained was excellent.

EXAMPLE 7 Example 5 was repeated, with the difference, however, that thecoating composition of the second subbing layer was replaced by thefollowing one:

20 1 latex of copolymer of butadiene,

ethyl acrylate and acrolein (55:40:5) 6 gr gelatin 0.80 g. water 60 ccs.methanol 40 ccst The adherence of the layers of the material wasexcellent.

EXAMPLE 8 Example 5 was repeated, but the coating composition of thesecond subbing layer was replaced by the following one:

20 1? latex of butadiene and acrylonitrile (60:40) 6 g. gelatin 0.80 g.water 60 ccs. methanol 40 ccs.

The adherence of the layers of the material obtained was excellent.

EXAMPLE 9 Example 5 was repeated, but the coating composition of thesecond subbing layer was replaced by the following one:

20 7; latex of copolymer of butadiene and ethyl hexyl acrylate (60:40) 6g. gelatin 0.80 g. water 60 ccs. methanol 40 ccs.

The adherence of the layers of the material obtained was excellent.

EXAMPLE 10 To a biaxially oriented polyethylene terephthalate film of180 p. thickness a layer was applied at 25 C. in a proportion of 2g./sq.m from the following composition:

copolymer of vinyl chloride, n-butyl acrylate, and methacrylic acid(70:26:4) 8 g. methylene chloride ccs. dichloroethane 20 ccs A secondlayer was applied thereto at 25 C. in a proportion of 0.6 g. per sq.mfrom the following coating composition:

20 latex of copolymer of hutadiene and ethyl acrylate (50:50) 6.25 g.gelatin 1 g. water 60 ces methanol 40 ccs.

The dried combination of subbing layers was coated successively with anantistatic gelatin layer and a light-sensitive gelatin silver halideemulsion layer as commonly used in X-ray photographic material. Thelayers of the material thus obtained showed an excellent adherencebefore, during as well as after processing.

ll EXAMPLE 11 To a biaxially oriented polyethylene terephthalate film ofI80 p thickness a layer was applied at 25 C. in a proportion of lg./sq.m from the following coating composition:

copolymer of vinylidene chloride. n-butyl-maleimide and itaconic acid(90:8:2) 8 g. methylene chloride 80 cos. dichloroethane 20 cos.

To this layer a second layer was applied at 35 C. in a ratio of 0.4 to0.6 g./sq.m from the following composition:

20 k latex of copolymer of butadiene and n-butyl acrylate (70:30) 6 g.gelatin 0.80 g. water 60 cos. methanol 40 cos.

This layer was coated successively with a known antistatic gelatin layerand a light-sensitive gelatin silver halide emulsion layer as commonlyused in X-ray material. The adherence of the layers was excellent.

EXAMPLE 1?.

To one side of a nonstretched polyethylene terephthalate film of about 1mm. thickness a layer was applied at 25 C. in a proportion of about 5g./sq.m from a latex of a copolymer of vinyl chloride, nbutyl acrylate,and itaconic acid (66:30:4).

This subbed film was simultaneously stretched longitudinally andtransversally to about ten times its original size. Another layer wasapplied at 40 C. to the vinylidene chloride layer in a proportion of 0.4to 0.6 g./sq.m from the following coating composition:

20 i latex of copolymer of butadiene and ethyl hexyl acrylate (60:40) 6g.

gelatin 0.80 g. water 60 ccs.

methanol 40 ccs.

The dried material was then coated with a gelatin silver halide emulsionlayer as commonly used for graphic purposes. The graphic material formedpossessed an excellent adherence of the layer in dry as well as in wetstate.

EXAMPLE 13 A first subbing layer as described in example 4 and a secondsubbing layer as described in example 3 were applied successively to abiaxially stretched polyethylene terephthalate support of l00 ,u.thickness. The resulting material was then coated with a light-sensitivelayer prepared as follows:

120 g. of zinc oxide was dispersed while stirring thoroughly in 700 ml.of demineralized water, to which 2 g. of sodium hexametaphosphate hadbeen added. A solution of 80 g. of gelatin in 820 g. of demineralizedwater, g. ofa 12.5 percent solution of saponine in demineralized water,and 10 g. of a percent solution of formaldehyde in demineralized waterwere added at 40 C. The mixture was then coated in a ratio ofapproximately 2 g. ofzinc oxide per sq.m.

The dried light-sensitive material was exposed image-wise through atransparent original and dipped in the following baths:

5 seconds in a 5 percent solution of silver nitrate in demineralizedwater;

5 seconds in a 0.6 percent solution of pmonomethylaminophenol sulphatein demineralized water;

seconds in an acid fixing bath containing 200 g. of sodium thiosulphate5 aq. and 25 g. of potassium metabisulphite per liter.

Subsequently the material was rinsed for 5 minutes in running water andthen dried. A black negative image of the original was obtained.

-12. EXAMPLE 14 A biaxially oriented polyethylene terephthalate supporthaving a thickness of ,u. was coated with a subbing layer consisting ofa solution in dichloroethane of a copolymer of vinylidene chloride,N-tert.butylacrylamide, n-butyl acrylate, and vinyl pyrrolidone preparedas described in example I, in such a way that the resulting dried layerhad a thickness of l p.

30 g. of titanium dioxide having a particle size of l5 to 40 mp. and aspecific surface of approximatively 50 sq.m./g. were stirred for 2 min.with cc. of demineralized water and 0.5 g. of sodium hexametaphosphateby means of an Ultra-Turrax stirrer, so that an homogeneous dispersionwas produced. To the resulting mixture a solution at 30 C. of 12.5 g. ofgelatin in 4l2.5 cc. of demineralized water and a 20 percent by weightlatex of a copolymer of butadiene and methyl methacrylate prepared asdescribed in example 1 were added successively while stirring. Finally,250 cc. of demineralized water at 30 C. were added.

The resulting pigment dispersion was applied to the polyester filmsubbed with vinylidene chloride copolymer in such a proportion that 1.59g. of titanium dioxide were present per sq.m. of the layer.

The dried material was then exposed image-wise through a transparentoriginal and dipped successively in the following baths:

1. 30 sec. in a 10 percent by weight solution of silver nitrate indemineralized water;

2. 30 sec. in a 3 percent by weight solution of pmonomethylaminophenolsulphate in demineralized water;

3. 60 sec. in an acid fixing bath containing 200 g. of sodiumthiosulphate 5 aq. and 25 g. of potassium metabisulphite per liter.

A sharp black negative silver image of the exposed original was obtainedupon rinsing and drying.

EXAMPLE 15 One side of a biaxially oriented polyethylene terephthalatefilm having a thickness of p. was coated with the following compositionat 25-30 C. in a ratio of 1.5 to 1.75 g./sq.m:

copolymer of vinylidene chloride, N-tert.-butylacrylamide, n butylacrylate. and Nvinyl pyrrolidone prepared as described in example I 5.5g. methylene chloride 65 cos. dichloroethane 35 cos.

The resulting layer was coated with a mixture of 95 parts by weight ofwater and 5 parts by weight of ethylenechlorhydrin, which mixturecomprises 13.5 percent by weight of titanium dioxide, 1.6 percent byweight of gelatin, and 5 percent by weight of a latex of the copolymerof butadiene and methylmethacrylate (50:50 percent by weight) preparedas described in example 1. Upon drying the layer formed had a thicknessof 4-5 .4.. The coating composition was prepared as follows: 2,025 g. oftitanium dioxide was dispersed in 7,500 cc. of water with 37 cc. ofhexametaphosphate as dispersing agent. The dispersion was stirred fastlyfor 10 min. at 5l5 C. and then heated to 35 C. A 10 percent by weightaqueous solution of gelatin was added thereto while stirring rapidly.The following composition was then added while stirring slowly to avoidscumming:

10 percent aqueous solution of gelatin 2600 ccs. water 300 ccs. 20 i byweight latex of the copolymer of butadiene and methyl methacrylateprepared as described in example 1 3750 ccs. l0 by weight aqueoussolution of the sodium salt of oleylmethyltauride 225 ccs.ethylenechlorhydrin 750 ccs.

Before coating the dispersion having a viscosity at 35 C of 8 cp. wasfiltered.

The butadiene copolymer layer was then covered with a gelatin silverhalide emulsion layer as known in the graphic art. The thus formedphotographic material can be used whenever a dimensionally stablesupport is needed and whenever the favorable light reflectioncharacteristics of the titanium dioxide layer are needed.

In certain applications the titanium dioxide can be replaced by otherpigments, e.g., silicium dioxide.

EXAMPLE 16 In the same way as in example 15, a biaxially orientedpolyester film is coated with a layer of a vinylidene chloridecopolymer. The resulting layer was coated with a composition comprising3 percent by weight of carbon black, 1 percent by weight of gelatin, and3 percent by weight of the copolymer of butadiene and methylmethacrylate prepared as described in example 1.

This composition was prepared as follows:

l87.5 cc. of a 16 percent by weight aqueous dispersion of carbon blackcomprising 2 percent by weight of poly-N-vinyl pyrrolidone wasdilutedwith 300 cc. of water. 5 cc. ofa 40 percent by weight latex of thecopolymer of ethyl acrylate and N- vinyl pyrrolidone (90:10 percent byweight) and 100 cc. of a percent by weight aqueous solution of gelatinwere added thereto at 35 C. The mixture was stirred rapidly for 5 min. Amixture at 35 C. of 150 cc. of a percent by weight latex of thecopolymer of butadiene and methyl methacrylate prepared as described inexample 1, l5 cc. ofa l0 percent by weight aqueous solution of thesodium salt of oleylmethyltauride, 5 ml. of a 40 percent by weight latexof the copolymer of ethyl acrylate and N-vinyl pyrrolidone (90:10percent by weight), and l87.5 ml. of water were added thereto whilestirring slowly. Subsequently 50 ml. of methanol were added. The mixturewas then filtered while warm.

The vinylidene chloride copolymer layer was coated with this compositionso that upon drying a layer having a thickness of 4-5 p. was formed.

The latter layer was then coated successively with a gelatin subbinglayer and a high-sensitive gelatin silver halide emulsion layer having asoft gradation.

The black-pigmented photographic material could be used for producingimages according to a silver complex diffusion transfer process, whereinthe sandwich formed by the lightsensitive and the image-receiving layercan be removed from the camera or the cassette during development of thenegative image and during the positive image formation by diffusiontransfer.

We claim:

1. Sheet material comprising a hydrophobic film support havingsuperposed thereon in succeeding order, a first layer directly adherentto said hydrophobic film support and comprising a copolymer formed from45 to 99.5 percent by weight of at least one vinylidene chloride orvinyl chloride monomer, from 0.5 to 10 percent by weight of anethylenically unsaturated hydrophilic monomer, and from O to 54.5percent by weight of at least one other copolymerizable ethylenicallyunsaturated monomer; and a second layer comprising in a ratio of 1:3 to1:05 by weight a mixture ofgelatin and a copolymer of 30 to percent byweight of butadiene with at least one copolymerizable ethylenicallyunsaturated monomer.

2. Sheet material according to claim 1, wherein the copolymer of saidfirst layer contains up to 54.5 percent by weight of at least oneacrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester,maleic acid ester or N-alkylmaleimide monomer.

3. Sheet material according to claim 1, wherein the said first layer isformed from a dried solution of a copolymer of vinylidene chloride,N-tert.butyl-acrylamide, n-butylacrylate, and N-vinyl pyrrolidone.

4. Sheet material according to claim 1, wherein the said first layer isformed from a dried solution of a copolymer of vinylidene chloride,N-tert.-butyl acrylamide, n-butyl acrylate and itaconic acid.

5. Sheet material according to claim 1, wherein the said first layer isformed from a dried solution of a copolymer of vinylidene chloride,vinyl chloride and methacrylic acid.

6. Sheet material according to claim 1, wherein the said first layer isformed from a dried solution of a copolymer of vinyl chloride, n-butylacrylate and itaconic acid.

7. Sheet material according to claim 1, wherein the said first layer isformed from a dried latex of a copolymer of vinylidene chloride, vinylchloride, n-butyl acrylate and itaconic acid.

8. Sheet material according to claim 1, wherein the said second layer isformed from a dried mixture of gelatin and a latex of a copolymer ofbutadiene and at least one acrylonitrile, styrene, acrylic acid esters,methacrylic acid esters or acrolein monomer.

9. Sheet material according to claim 8, wherein the copolymer ofbutadiene is a copolymer of butadiene and methyl methacrylate.

10. Sheet material according to claim 8, wherein the copolymer ofbutadiene is a copolymer of butadiene and acrylonitrile.

11. Sheet material according to claim 8, wherein a matting agent hasbeen added to the mixture of gelatin and butadiene copolymer latex.

12. Sheet material according to claim 11, wherein the matting agent isfinely divided silica.

13. Sheet material according to claim 8, wherein an antistatic agent hasbeen added to the mixture of gelatin and butadiene copolymer latex.

14. Sheet material according to claim 1, wherein the hydrophobic filmsupport is a cellulose triacetate film.

15. Sheet material according to claim 1, wherein the hydrophobic filmsupport is a biaxially oriented polyethylene terephthalate film.

16. Sheet material according to claim 1, wherein the first layer hasbeen applied to an unstretched polyethylene terephthalate film, which isthen oriented biaxially.

17. Sheet material according to claim 1, wherein the first layer hasbeen applied to a polyethylene terephthalate film oriented in only onedirection, which is then oriented in a direction perpendicular to thefirst one.

18. Sheet material according to claim 1 including a separate hydrophiliccolloid layer containing gelatin on the side of said second layer remotefrom said film support.

2. Sheet material according to claim 1, wherein the copolymer of saidfirst layer contains up to 54.5 percent by weight of at least oneacrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester,maleic acid ester or N-alkylmaleimide monomer.
 3. Sheet materialaccording to claim 1, wherein the said first layer is formed from adried solution of a copolymer of vinylidene chloride,N-tert.butyl-acrylamide, n-butylacrylate, and N-vinyl pyrrolidone. 4.Sheet material according to claim 1, wherein the said first layer isformed from a dried solution of a copolymer of vinylidene chloride,N-tert.-butyl acrylamide, n-butyl acrylate and itaconic acid.
 5. Sheetmaterial according to claim 1, wherein the said first layer is formedfrom a dried solution of a copolymer of vinylidene chloride, vinylchloride and methacrylic acid.
 6. Sheet material according to claim 1,wherein the said first layer is formed from a dried solution of acopolymer of vinyl chloride, n-butyl acrylate and itaconic acid. 7.Sheet material according to claim 1, wherein the said first layer isformed from a dried latex of a copolymer of vinylidene chloride, vinylchloride, n-butyl acrylate and itaconic acid.
 8. Sheet materialaccording to claim 1, wherein the said second layer is formed from adried mixture of gelatin and a latex of a copolymer of butadiene and atleast one acrylonitrile, styrene, acrylic acid esters, methacrylic acidesters or acrolein monomer.
 9. Sheet material according to claim 8,wherein the copolymer of butadiene is a copolymer of butadiene andmethyl methacrylate.
 10. Sheet material according to claim 8, whereinthe copolymer of butadiene is a copolymer of butadiene andacrylonitrile.
 11. Sheet material according to claim 8, wherein amatting agent has been added to the mixture of gelatin and butadienecopolymer latex.
 12. Sheet material according to claim 11, wherein thematting agent is finely divided silica.
 13. Sheet material according toclaim 8, wherein an antistatic agent has been added to the mixture ofgelatin and butadiene copolymer latex.
 14. Sheet material according toclaim 1, wherein the hydrophobic film support is a cellulose triacetatefilm.
 15. Sheet material according to claim 1, wherein the hydrophobicfilm support is a biaxially oriented polyethylene terephthalate film.16. Sheet material according to claim 1, wherein the first layer hasbeen applied to an unstretched polyethylene terephthalate film, which isthen oriented biaxially.
 17. Sheet material according to claim 1,wherein the first layer has been applied to a polyethylene terephthalatefilm oriented in only one direction, which is then oriented in adirection perpendicular to the first one.
 18. Sheet material accordingto claim 1 including a separate hydrophilic colloid layer containinggelatin on the side of said second layer remote from said film support.